Immobilization of urease onto membranes of modified acrylonitrile copolymer

Urease was immobilized onto membranes prepared from acrylonitrile (AN) copolymer (powder) modified preliminarily with 2-dimethylaminoethyl methacrylate (DMAEM) and diacrylamido-2-methylpropanesulfonic acid (AMPSA). The results obtained were compared with those from commercial acrylonitrile copolymer membranes surface modified with DMAEM and AMPSA under the same conditions. The preliminary treatment was found to give higher amount of active groups and higher modification degree compared to surface modified acrylonitrile copolymer membranes. The modified membranes were used as carriers for immobilization of urease. The basic characteristics of the immobilized urease (amount of bound protein and relative activity) were studied. Temperature and pH optima and thermal stability of the immobilized urease were also studied. The membranes prepared from AN copolymer (powder) modified with AMPSA and DMAEM were used to manufacture diagnostic test-strips for analysis of urea in blood.